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Quantum dot emitter delivers near-identical telecom photons at 40 million per second

Quantum technologies, devices that perform specific functions leveraging quantum mechanical effects, could soon outperform their classical counterparts on some tasks. Quantum emitters, devices that release individual particles of light (i.e., photons), are central components of many of these technologies, including quantum communication systems and quantum computers.

To enable the reliable operation of quantum technologies, emitters should emit photons with high consistency and coherence. In other words, they should ensure that the quantum properties of emitted photons remain stable and predictable.

Researchers at University of Copenhagen’s Niels Bohr Institute, Ruhr-University Bochum, University of Basel and Sparrow Quantum ApS recently developed a new photon emitter based on quantum dots, tiny structures that can trap electrons in confined regions and enable the controlled emission of individual photons.

Hybrid AI architecture could turn neuromorphic systems into reliable discovery machines

The artificial intelligence (AI) machines that guide the world can be grouped into three main categories: inference machines, learning machines and discovery machines. Researchers at Washington University in St. Louis are tackling the rarest of these machines. A new study points to a better way to build discovery machines, thanks to recent research led by Shantanu Chakrabartty, the Clifford W. Murphy Professor and vice dean for research in the McKelvey School of Engineering at Washington University in St. Louis.

The work, now published in Nature Communications, builds off previous research on establishing a hybrid systems architecture, one that employs “neuromorphic” architecture modeled on human neurobiology functions combined with systems that leverage quantum mechanics to find optimal solutions to complex problems.

The research shows that these machines can consistently produce state-of-the-art solutions with high reliability and with competitive time-to-solution metrics, Chakrabartty said.

How a single star can reshape an entire galaxy

Astronomers who simulate galaxies do not always get the same result, even when they start from identical conditions. New research from Leiden University shows that this is not a flaw, but a consequence of how galaxies behave—and how they are modeled.

The findings offer, for the first time, a way to address a long-standing question: how chaotic is a galaxy like the Milky Way really? The computer simulations by Tetsuro Asano and Simon Portegies Zwart (Leiden Observatory) will soon be published in Astronomy & Astrophysics and are available now on the arXiv preprint server.

The researchers created hundreds of models of Milky Way-like galaxies: flat disks of stars, embedded in a large, invisible cloud of dark matter that holds the system together. In each experiment, they ran two almost identical simulations, differing by just one tiny detail—for instance, a small shift in the position of a single star. Over time, that slight difference grows into visible structural changes: the spiral arms develop differently and the central bar rotates in another way.

‘Elegant triangle’ experiment suggests quantum internet may be closer than we think

For more than 60 years, Bell’s theorem has been the gold standard for demonstrating that quantum mechanics defies the rules of classical physics. Now, an international team of researchers, including Constructor University Professor Dr. Nicolas Gisin, has extended this principle to new limits, using an “elegant triangle” to reveal new forms of quantum nonlocality that specifically emerge in multi-node quantum networks.

The study, published in Physical Review Letters, opens a new frontier in our understanding of how quantum correlations behave in realistic network settings, one that could help usher in the age of a quantum internet.

“This is not simply a more elaborate version of Bell’s theorem applied to networks, it’s something genuinely new that only emerges when multiple independent quantum sources interact through entangled measurements,” explained Dr. Gisin, who collaborated on the experiment with researchers from China, France and Austria.

Light reshapes metal-organic framework to harvest airborne water

Chemists at the University of Iowa have created a three-dimensional lattice that captures water from the air and stores it. In a new study appearing in the Journal of the American Chemical Society, researchers describe a millimeter-scale structure made of metal atoms connected by two types of organic molecules. When exposed to ultraviolet light, the material undergoes a chemical reaction that changes its shape, creating cavities throughout the lattice. Those cavities attract water molecules from the air and store them—like a multitude of tiny canteens.

The results, which would need to be tested at larger scales, show promise as a method to help provide drinking water to people and areas with limited access. Water stress or scarcity will affect nearly five billion people—half the world’s projected population—by 2050, according to the United Nations.

“We have found and validated a way to capture and to store water that would require only sunlight,” says Leonard MacGillivray, adjunct professor in the Department of Chemistry and former professor and department chair. “You can transport the crystal lattice and eventually release the water on demand. That’s why it’s such an advance.”

Unexplored interactions between electrons and atomic nuclei shed light on dark matter

Dark matter particles could be mediators of the interaction between electrons and atomic nuclei, as shown by a study conducted by junior group leader, Dr. Konstantin Gaul, Dr. Lei Cong, and Professor Dr. Dmitry Budker, of Johannes Gutenberg University Mainz (JGU), Helmholtz Institute Mainz (HIM) and the PRISMA++ Cluster of Excellence. Their work, published last week in Physical Review Letters, presents new constraints on previously unexplored candidates for dark matter and, more generally, some hypothetical particles that are not included in the Standard Model of particle physics ℠.

Using results from precision measurements on barium monofluoride (BaF) molecules, the team constrained these interactions mediated by Z’ bosons for the first time. Z’ bosons are hypothetical mediators of the weak interaction and possible dark matter particles in several SM extensions. “These results address a significant blind spot in physics: a regime of forces between electrons and nuclei that had remained unexplored by both laboratory experiments and cosmological data,” explained Gaul.

Our universe is made up of about 4% of visible, or ordinary, matter. This includes planets, stars, and life on Earth. The remaining 96% of the universe is invisible and consists of dark matter and dark energy, with dark matter making up about 23%. Astrophysical observations confirm its presence throughout the cosmos, where it, for example, plays an important part in the structure of galaxies. However, we don’t know what particles make up dark matter. Many theories and ongoing experiments are looking for an answer to this open question.

Researchers find coherent ferrons—polarization waves with potential across quantum and telecom applications

In new research published in Nature Materials, a team of researchers led by Columbia University chemist Xiaoyang Zhu, in collaboration with fellow Columbians Xavier Roy, Milan Delor, Dmitri Basov, and James McIver, has observed coherent ferrons for the first time.

Ferrons are electronic quasiparticles, predicted since the 1960s, that carry polarization. The oscillating polarization wave that the team, led by Columbia postdocs Jeongheon Choe and Taketo Handa, observed represents a new type of information carrier that could prove much faster than conventional electronics.

In ferroelectric materials, the dipole moments of unit cells line up, becoming polarized. Collective excitation of these dipoles creates the ferron quasiparticle, which has an inherent dipole moment. This means one side of each tiny particle is slightly more negatively charged than the other. Ferrons are similar to another quasiparticle that’s been of interest to Zhu and colleagues in recent years: magnons.

Chip-scale photonic approach achieves ultralow-noise microwave and millimeter-wave signal generation

Researchers led by Dr. Changmin Ahn and Prof. Jungwon Kim at KAIST, in collaboration with Prof. Hansuek Lee, have demonstrated a chip-scale photonic approach for generating ultralow-noise and highly stable microwave and millimeter-wave signals based on optical frequency combs (microcombs), offering a potential pathway toward compact, high-performance frequency sources for next-generation technologies.

High-frequency signals in the tens to hundreds of gigahertz range are essential for emerging applications such as 6G communications, radar, and precision sensing. However, achieving both low noise and high stability at these frequencies remains a fundamental challenge for conventional electronic signal sources.

In the first study, published in Laser & Photonics Reviews, the researchers addressed the long-standing challenge of transferring the stability of an optical reference to a microcomb. Direct stabilization is difficult due to the lack of carrier-envelope offset detection in high-repetition-rate microcombs. To overcome this, they used a mode-locked laser as a transfer oscillator and synchronized it to the microcomb using electro-optic sampling.

Lab-grown diamond device could change how radiation doses are measured

A team led by researchers from Tokyo Metropolitan University, in collaboration with Tohoku University and Orbray Co., Ltd., using heteroepitaxial diamond materials developed by Orbray, have shown that lab-grown diamonds might realize a radiation dosimeter compatible with both medical diagnosis and radiation therapy.

The work is published in the journal Medical Physics.

They demonstrated that a diamond-based dosimeter could accurately measure doses in the same energy range as diagnostic X-rays, with far better sensitivity per volume than conventional detectors. Using the same device for dosimetry during both diagnosis and therapies could enable improved consistency.

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